Considerations

Overview

ZStack Cloud provides high availability (HA) for dual-management node by using separate HA suites. When any one of the MNs is disconnected, the HA will be triggered in seconds to ensure the business continuity.

HA Mechanism: Each MN runs a zsha2 HA process. This process monitors the critical services, including the MN service, UI service, and database service, on each MN in real time. When any critical service is down, the Cloud immediately triggers virtual IP (VIP) migration through Keepalived, and then attempts to restore the downtime service.

Taking the dual-MN HA scenario as an example, this section introduces how to install, deploy, and upgrade a dual-MN HA environment and other related considerations. For detailed information, see Dual-MN HA Tutorial.

Installation and Deployment

• Switch a Single-MN Scenario to a Dual-MN HA Scenario
  1. Download the latest software packages, including ZStack Cloud ISO, ZStack Cloud installation package and Multi-MN HA Suite.
  2. Upgrade ZStack Cloud to the latest version on the local MN (MN1).
  3. Install the latest ZStack Cloud on the new MN (MN2).
  4. Install the license for MN2. In this scenario, the license type of two MNs must be the same.
  5. Import the HA suite to MN1. Then decompress and install the suite.
• Deploy a New Dual-MN HA Scenario
  1. Download the latest software packages, including ZStack Cloud ISO, ZStack Cloud installation package and Multi-MN HA Suite.
  2. Install the latest ZStack Cloud on the two new MNs.
  3. Install the license for the two new MNs. In this scenario, the license type of two MNs also must be the same.
  4. Import the HA suite to either MN. Then decompress and install the suite.

Upgrade

• Upgrade the HA Suite

  After you obtain the new HA suite, you can use the suite to upgrade the existing zsha2 service.

  If the databases of the two MNs are automatically synchronized, import the HA suite to the active MN and decompress it. Run the following command on the active MN to complete the upgrade of the HA suite:

  [root@localhost ~]# ./zsha2 upgrade-ha

• Upgrade the MNs

  In the dual-MA HA scenario, you must upgrade the HA suite before upgrading the MNs.

  Run the following commands on either MN. Then, both MNs will be upgraded:

  • If you upgrade the MN from the bin package, run the following command:

    [root@localhost ~]# zsha2 upgrade-mn -peerpass password ./ZStack-Cloud-installer-5.3.28.bin

  • If you upgrade the MN from ISO, run the following command:

    [root@localhost ~]# zsha2 upgrade-mn -peerpass password ./ZStack-Cloud-x86_64-DVD-5.3.28-h84r.iso

    Note: The -peerpass parameter is optional. You can use this parameter to set the SSH login password for the peer MN.

Considerations

• MNs must meet the configuration requirements: 8 CPUs plus 12GB memory or higher.
• We recommend that you use a 10-Gigabit or above bandwidth for the management network. If the management network is deployed independently, a 1-Gigabit bandwidth is allowed.
• We recommend that you create a static bridge via zs-network-setting.
• The multi-MN HA suite requires and must be paired with ZStack Cloud of 2.6.0 version and above. For example, HA suite 2.6.0 must be paired with ZStack Cloud 2.6.0.
• The ZStack Cloud version and the license type of two MNs must be the same.
• To install the HA suite, you need to put zsha2 and zstack-hamon in the same directory. During installation, zsha2 will automatically deploy zstack-hamon and other related configuration files.
• During installation, the database of the standby MN will be overwritten by that of the active MN. Please exercise caution.
• To ensure the real-time synchronization of monitoring data between two MNs, we recommend that you configure SSH password-free login for the two MNs.
• The Chrome browser used to access MNs requires version 49 or later.